Scores of screaming teenagers queued in the city centre to catch a glimpse of the British pop star.
Fans started gathering at 6am - almost seven hours before the teenage singer was due to arrive - for their chance to meet him.
First in the queue for the CD signing at HMV on Buchanan Street were Joanne Clarke, 17, from Eaglesham, and her 12-year-old cousin Erin Murray from Ayr.
The queue snaked from Buchanan Street and into Sauchiehall Street as fans waited for hours to get their hands on a wristband.
College student Joanne said: "I'm a massive fan of Elyar and I've watched him since he first started singing on YouTube.
"I just had to come down and see him today."
The 18-year-old will meet fans, play live and sign copies of his new single A Billion Girls at 12.30pm.
Erin, who had to get up at 5am to see her idol, said: "It was really hard getting up that early, but it was definitely worth it."
Access to the in-store performance will be limited to those who picked up the free wristbands from the shop.